Piston ring



Nov. 20, 1945. c F ENGELHARDT 2,389,l 4l

PISTON RING Filed May 19, 1942 3 ShGetS -Sheet l Nov. 20, 1945. c. F. ENGELHARDT 2,389,l41

PI STON RING Filed May 19, 1942 3 Sheets-Sheet 2 L. QF T Patented Nov. 20, 1945 &389.141

PISTON RING Carl F. Engelhardt, Yeadon, Pa., assignoto Wilkening Manufacturing Company, Philadelphia, Pa., a. co-poratlon of Delaware Application May 19, 1942, Serial No. 3,601

4 Claims.

The present invention relates to certain new and useful improvements in piston rings and it relates more particularly" to oil-control piston rings adapted for use in internal combustion engines.

An object of the present invention is to provide a simple, inexpensive and emcient piston ring for use in internal combustion engines. Another object of the present invention is to provide a piston ring formed of one or more strips of sheet metal or the like suitably bent and folded to provide an interlocked composite structure having continuous axially-separated cylinder- Contacting ribs and having oil-drain passages therethrough.

Other objects and advantages of the present invention are apparent in the following specification, appended claims and accompanying drawings.

For the purpose of illustrating the invention, there are shown in the accompanying drawings forms thereof which are at present preferred, since the same have been found in practice to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangements and organizations of the instrumentalities as herein shown and described.

Referring to the accompanying drawings in which like reference characters indicate like reference parts throughout:

Figure 1 represents a perspective view of an annulus formed of a strip of sheet metal or the like and constituting a part of one embodiment of the present invention. v

Figure 2 represents a perspective view similar to that of Figure 1 but showing an annulus complementary to that in Figure 1, and adapted to be used therewith.

Figure 3 represents a perspective view similar to that of Figures 1 and 2 but showing the two annuli in assembled position in which they make up a more or less unitary piston ring.

Figure 4 represents a cross-sectional view generally along the line 4-4 of Figure 3.

Figure 5 represents a cross-sectional view generally along the line 5-5 of Figure i.

Figure 6 represents a vertical cross-sectional view generally along the line 6-6 of Figure 4.

Figure 7 represents a fragmentary perspective view on an enlarged scale of a modified annulus which may be used in place of the annulus of Figure 1 in another embodiment of the present invention.

Figure 8 represents a fragmentary perspective view on an enlarged scale of an annulus which may be used with the annulus of Figure 7.

4 Figure 9 represents a fragmentary perspective cylinder-contacting edge.

view showing the assembled embodiment constructed using the annuli illustrated in Figures 7 and 8.

Figure 10 represents a fragmentary edge elevational view of the embodiment illustrated in Figure 9.

Figure 11 represents a vertical cross-sectional View generally along the line ll--ll of Figure 10 showing the embodiment as it appears when assembled on a piston in a cylinder.

Figure 12 represents a vertical cross-sectional view generally along the line l2-l2 of Figure 10.

Figure 13 represents a perspective view of a one-piece embodiment of the present invention as it appears when disassembled and helically extended.

Figure 14 represents a fragmentary edge elevational view of the embodiment illustrated in Figure 13, showing the zone of "cross-over" forming the juncture of the upper and lower turns of the helix as it appears when the ring is assembled.

In one embodiment of the present invention shown generally in Figures 1 to 6, I may provide an annulus designated generally by the reference character o and illustrated in Figure 1, and another annulus designated generally by the reference character ll and illustrated in Figure 2.

The annuli I!! and ll are formed of strips of sheet metal suitably bent and folded into axiallycorrugated unitary rings as illustrated.

The annulus o shown in Figure 1 is made up of alternate upper segments z and lower segments !3. The segments [2 lie generally in a single radial plane and the segments |3 lie generally in a single radial planethe two planes being axially separated.

Successiva segments |2 and !3 are connected by generally axially-extending portions ll which are formed integrally therewith and at generally obtuse angles thereto. The segments |2 and l3 are inwardly tapered generally along the lines of radius of the annulus o.

Oppositely-axially-extending free ends |5 and IS of the annulus lll are overlapped to provide a more or less complete ring.

The axially-extending portions !4 are cut away along the radially inner edges as at I 'I slightly more than half the radial dimension thereof.

The radially outer edges |8 and !9 of the segments l2 and l3 respectively, together with the radially outer edges 20 of the portions 14, form a generally continuous non-sinuously corrugated Because of the cutaway edges l'l of the portions !4, the annulus n does not have a continuous edge along its radially inner periphery; the radially inner edges 2| and 22 of the segments |2 and [3, respectively, being spaced from each other circumferentially and axially.

' extending portions 25 which are formed integrally with and at obtuse angles to, said segments 23 and 24.

The oppositely-axially-extending free ends 26 and 21 of the annulus Il are overlapped to provide a more or less continuous ring. The axiallyextending portions 25 of the annulus ll are cut away as at 23 along their radially outer edges for slightly more than half the radial dimension thereof. Thus, the radially outer edges 29 and 30 of the segments 23 and 24 respectively are spaced from each other to form an interrupted cylinder-Contacting edge. while the radially inner edges 3| and 32 of said segments 23 and 24, together with the radially inner edges 33 of the portions 25, form a continuous non-sinuously corrugated edge along the inner periphery of said annulus Il.

The radially outer edges IB, IS and 20 of the annulus o and the radially outer edges 29 and 30 of the annulus I I are curved, by grinding or other suitable forming Operations, to conform to the cylindrical surface of the particular size cylmder in which the piston-ring is adapted to be used.

The annuli and ll may be assembled into the composite piston-ring shown in Figura 3. In the assembled position shown in Figures 3 and '4, the upper segments Iz of the annulus !0 are in altemating juxta-position to the upper segments 23 of the annulus ll. similarly, the lower segments l3 of the annulus l0 are in alternating juxta-position to the lower segments 24 of the annulus ll.

The axially-extending portions |4 of the annulus !0 are disposed adjacent to; and radialy outward of, the axially-extendng portions 25 of the annulus ll as shown in Figures 5 and 6; the portions |4 fltting within the cut-away edges 20 of the portions 25, and the portions 25 fitting within the cut-away edges I'I of the portions l4. As shown particularly in Figure 4, the portions |4 and 25 extend in oppositely-angled directions.

The annu1i.|0 and H are preferably so assembled that the freeends I5 and !6 of the annulus l0 are circumferentially spaced from the free ends 25 and 21 of the annulus ll as shown in Figure 3.

The fol'd-lines separating the segments from the axially-extending portions are preferably formed as sharp edges by coining or other suitable Operations whereby the adjacent segments will make firm and continuous contact with each other as shown in Figures 3 and 4 to provide a generally fiuid-tight seal`therebetween. When the piston-ring is assembled within the groove 34 of a piston 35 and installed within a cylinder 36, as shown in Figure 6, the piston-ring is compressed slightly, both radially and circumferentialy; the ring having inherent resiliency whereby it will tend to expand radially and circumferentially against the cylinder Wall and to make firm contact therewith, without the use of a separate expander spring.

As shown particularly in Figures 3 and 4, the annuli lo and ll together form a series of circumferentially-disposed radially-extending oilpassageways 31, through which oil, wiped from the cylinder wall -by the outer cylinder-contacting edges of the piston-ring, is passed into thegroove 34 and the oil drain passageway 30 of the piston 35 and returned to the crankcase.

The radially-adjacent axially-extending portions |4 and 25 have a slight clearance 39 radially therebetween whereby the annull l0 and I I are free to move axially and radially of each other to a limited extent, thereby to permit the pistonring better to conform to any irregularities in the cylinder wall such as might be caused by wear.

In Figures 7 to 12' inclusive, there is shown a modified form of the present invention.

In the embodiment of Figures 7 to 12, annulus lol-a shown in Figura 8 is employed which may be identical with the annulus shown in Figure 2. However, the complementary annulus l0--a of this em'bodiment is modified somewhat from the annulus l0 of Figur-e 1 in that the outer edges 20-a of the axially-extending portions l4--a are recessed slightly from the outer edges lB--a and l9-a of the upper and lower segments |2-a and l3-a respectively. Thus, when the piston-ring is finally assenrbled, it makes contact with the cylinder wall only along the axially-spaced, more or less continuous annular ribs formed respectivel by adjacent upper segments l2 and 23 and by adjacent lower segments l3 and 24 as shown in Figura 11.

This embodiment may in some respects be prefer-red since the contact area between the piston and the cylinder is reduced, thus giving a greater unit pressure and furthermore reducing wear.

In Figures 13 and 14 there is shown another embodiment of the present invention in which the piston-ring is constructed from a single helical strip having two complete turns. In the embodiment of Figures 13 and 14, a helical sheet metal strip indicated generally by the reference character 40 is provided with alternating upper segments 4I and lower segments 42; the segments 4| and 42 being axially displaced.

Successive segments 4| and 42 are connected by generally axially-extending portions 43 which are formed integrally with, and at obtuse angles to, said segments 4l and 42.

The axially-extending portions 43-a of one complete turn (as for example the upper turn shown in Figure 13) of the strip 40 are cut out as at 44 along their inner peripheral edges for slightly more than half the radial dimension of said portions 43-a. The axially-extending portions 43-b of the other turn (as for example the lower turn shown in Figur-e 13) of the strip 40 are cut out as at 45 along their outer peripheral edges for slightly more than half the radial dimension of said portions 43-b.

The cross-over segment 46 integrally connects the two turns of the strip 40 and has one axiallyextending portion 43-a cut out along the inner peripheral edge as at 44 and the other axiallyextending portion 43-b cut out along the outer peripheral edge as at 45; the segment 46 thereby effecting the transition from the Construction of one tum to the Construction of the other turn of the member 40.

The strip 40, when its free ends 41 and 40 are spread axially apart, assumes the helical form shown in Figure 3. When, however, the free ends 41 and 48 are released, the natural resiliency of the strip 40 causes it to spring together. When the strip 40 is permitted to come together from the form shown in Figure 13 and the cross-over segment 46 is pressed radially inwardly, the upper and lower turns will dove-tail within each other .to provide the generally closed Construction shown in Fgure 14. That is, the axially-extending portions 43-b of the lower turn fit within the cut-out edges 44 of the portions 43--a while the portions 43-a fit within the cut-out edges 45 of the portions 43--b. As shown in Figure 14, the portions 43-a and 43-b' are oppositely inclined in the internested position of the strip 40.

Except for the cross-over segment 46 and the free ends 41 and 48, the strip 40, in its closed position, has generally the same construction as the embodiment shown in Figures 3 and 4 in that a plurality of circumferentially-spaced radially-extending oil passageways 49 are provided intermediate a pair of axially-spaced more or less continuous cylinder-contacting ribs.

The free ends 41 and 48 may be seated against each other in any suitable manner as for example in the manner shown in Figure 14 in which the free ends are placed radially adjacent to each other and terminate axially adjacent the cross-over segment 46.

Other modifications of the construction shown in Figures 13 and 14 are apparent and are within the scope of the present invention, Thus the outer peripheral edges of the axially-extending portions 43-a could be cut away as in Figure 7 so that, in the final closed form the strip would be grooved about its outer periphery as in Figures 9, ll and 12 and so that the axially intermediate portion would be recessed from the cylinder walls; contact with the cylinder wall being made only along the axially-spaced ribs.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having thus described the invention, what is hereby claimed as new and desired to be Secured by Letters Patent is:

1. A piston-ring formed of ribbon-like sheet metal or the like comprisng interlaced annular axially-corrugated portions, each having successive plane segments disposed alternately in axially-separated radial planes and plane interconnecting portions formed integrally with said segments and at obtuse angles thereto, said segments having straight-line edges formed as radii of the piston ring said interconnecting portions having a smaller radial dimension than said segments, the segments of the respective annular portions being circumferentially displaced and staggered in altemate juxtaposition to provide axially-separated more or less continuous annular cylinder-contacting ribs, the interconnecting portions of the respective annular portions being radially substantially separated from each other when said axially-separated ribs have their cylinder-contacting edges axially aligned, whereby said interconnecting portions of the respective annular portions are capable of free radial movement.

2. An oil-control piston-ring comprising a pair of preiormed resilient annuli of sheet metal or the like, each annulus being axially non-sinuous ly corrugated to provide successive plane segments disposed altemately in axially-separated radial planes and radially-reduced interconnecting portions formed integrally with said se ments, said segments having straight-line edges formed as radii of the piston ring, said annuli being complementary and being interlacedl and separably assembled in radially-nested relationship, the interconnecting portions of the respective annuli being radially su-bstantially separated from each other when the outer edges of said annuli are axially aligned, whereby said interconnecting portions of the respective annuli are capable of free radial movement.

3. An oil-control piston-ring comprising a pair of preformed annuli of sheet metal or the like, each axiall non-sinuously corrugated to provide segments lying alternatel in spacedradia planes and narrow interconnecting A portions formed integrally with said segments, said se ments having straight-line edges formed as radii of the piston ring, the interconnecting portions of one annulus being disposed at the radially outer periphery thereof and the interconnecting portions of the other annulus being disposed at the radially inner periphery thereof, the radiallyouter-most edges of said first-mentioned interconnecting portions being recessed from the outermost radial edges of the segments, said 'annuli being interlacedly assembled with their respective interconnecting portions in radial Juxtaposition and with their respective segments disposed in alternate circumferential juxtapsition to provide a pair of more or less continuous axially-separated cylinder-contacting ribs separated by a more or less continuous annular groove, said annuli providing a plurality of circumferentially-disposed oil-passageways extending radially from said groove to the inner periphery of said ring, the interconnecting portions of the respective annuli being radially substantially separated from each other when the outermost radial edges of the segments of the respective annuli are axially aligned, whereb said interconnecting portions of the respective annuli are capable of free radial movement 4. An oil-control piston-ring for use in cylinders of internal combustion engines comprising interlaced annular axially-corrugated portions, each having axially-staggered plane segments lying alternately in axially-spaced radial planes and generally axially-extending radielly-reduced interconnecting portions formed integrally with a said segments and at obtuse angles thereto, said segments having straight-line edges formed as radii of the piston ring, the plane segments of respective annular portions being circumferentially displaced and staggered to provide axiallyseparated more or less continuous annular cylinder-contacting ribs, the interconnecting portions of respective annular portions being radially displaced to permit repeated intercrossing thereof, said interconnecting portions being recessed from the outer peripheral edge of said plane segments whereby said piston ring makes contact with the cylnder wall only along said annular ribs, and said interconnecting portions being radially substantially separated from each other when sad axially-separated ribs have their cylinder-contacting edges axially aligned, whereby said interconnecting portions of the respective annular portions are capable of free radial movement.

CARL F, ENGELHARDT. 

